Administration of intravenous fluids to a patient is well known in the art. Typically, a solution such as saline, glucose or electrolyte in a glass or flexible container is fed to a patient's venous access site via a length of flexible plastic I.V. tubing such as polyvinyl chloride (PVC) tubing. The rate of flow of the fluid is controlled by a roller clamp which is adjusted to restrict the flow lumen of the I.V. tubing until the desired flow rate is obtained.
Flow from the container to the patient may also be regulated by means other than a roller clamp. It is becoming more and more common to use an electronically controlled pump. One type of pump that is used for intravenous fluid administration is a peristaltic-type pump.
Use of peristaltic pumping action is particularly well suited for the medical field. This is because peristaltic pumping action can be applied externally of the I.V. tubing carrying the intravenous fluid. This maintains the sterile condition of the intravenous fluid within the I.V. tubing while imparting fluid propulsion on the fluid. The peristaltic pumping action can also be applied on any point on the I.V. tubing.
In a common type of peristaltic pump used in the medical field, a driving motor is connected to an array of cams which are angularly spaced from each other. The cams in turn drive cam followers which are connected to corresponding pressure fingers. These elements cooperate to impart a linear wave motion on the pressure fingers. A pressure plate is secured juxtaposed to and spaced from the pressure fingers. The pressure plate holds the I.V. tubing against the reciprocating pressure fingers to impart the wave motion on the I.V. tubing to propel the fluid.
In another common type of peristaltic pump used in the medical field, a driving motor is connected via an armature to at least one roller member. The driving motor imparts a circular rotation on the armature which actuates the roller member. A semicircular pressure plate having the same center point as the armature is provided with the I.V. tubing located between the roller member and the pressure plate. The pressure plate holds the I.V. tubing against the roller member which imparts a circular motion on the I.V. tubing to propel the fluid.
One drawback of the use of peristaltic pumps is that, because when loaded into the pump the peristaltic action drives the propulsion of the fluid, prior to loading into the pump, the I.V. tubing is often left in an open condition. While a straightforward solution to this problem is to simply provide a roller or other flow clamp on the I.V. tubing to occlude the I.V. tubing prior to loading and after removal, this creates the possibility that the health care professional loading the I.V. tubing into the peristaltic pump will forget to open the I.V. tubing after loading has been completed. While a solution which includes a dedicated flow clamp and housing which is loaded into the peristaltic pump has been provided, this solution has several drawbacks, including the dedicated use of such a flow clamp assembly for a select peristaltic pump and the ease in which the locking mechanism can be bypassed manually by a health care professional. Moreover, because this solution employs a dedicated slide clamp, health care professionals must take care to remove the slide clamp before disposal of the I.V. tubing.
Prior art slide clamps generally include a regulating aperture defining an occluding slot and a non-occluding passage. An I.V. tube inserted through the regulating aperture in an operative position is slidable transverse to the length of the tube between the non-occluding passage and the occluding slot to control the flow of fluid through the lumen of the I.V. tube. With the I.V. tube in an operative position in the non-occluding passage, prior art slide clamps tend to slide longitudinally of the I.V. tube under the effect of gravity. Often, this sliding makes it difficult and cumbersome for medical personnel to quickly locate the slide clamp to occlude flow at a desired position along the length of the I.V. tube. In addition, the tube contacting surface of the flow regulating aperture typically extends over the entire depth of the slide clamp. As a result, prior art slide clamps leave a relatively wide surface contacting an I.V. tube in an operative position, providing a significant frictional force opposing sliding of an I.V. tube relative to the slide clamp between the non-occluding passage and the occluding slot. Both of these features make it relatively difficult to use prior art slide clamps with a safety mechanism for use in a peristaltic pump. First, it can be difficult for a health care professional to locate the slide clamp for insertion into a slide clamp receiving slot in the peristaltic pump and second, once inserted, prior art slide clamps may offer too much frictional resistance for the safety apparatus to drive the slide clamp between the occluded slot and the non-occluding passage.
What would thus be advantageous would be a safety mechanism for use in a peristaltic pump which utilizes a disposable I.V. slide clamp carried by I.V. tubing which can be located longitudinally of the tube and not displaced solely by force of gravity and which can be slid between a non-occluding passage and an occluded slot with minimal force. The safety mechanism would preferably prevent both an inadvertent free flow condition prior to loading or after removal of an I.V. tube in a peristaltic pump and prevent inadvertent occlusion of a loaded I.V. tube.